• Title/Summary/Keyword: 터보차저 소음

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Improvement of engine noise causing rough sound quality (거친 청감을 유발하는 엔진소음 개선 방향 고찰)

  • Jung, Insoo;Kim, Sukzoon;Cho, Teockhyeong
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.4
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    • pp.242-247
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    • 2018
  • The automotive industry is making various efforts to cope with ever-increasing exhaust emissions and fuel economy regulations. However, this often results in degraded NVH (Noise, Vibration, and Harshness) performance. For example, we proposed the causes and improvements for the noise generated by the high-pressure pump noise of a gasoline engine, the change of acceleration noise due to dual injection of MPI (Multi-Point Injection) and GDI (Gasoline Direct Injection), the noise of a gasoline turbocharger, and the combustion noise deteriorated due to the injection parameters calibration in a diesel engine. Since these noises are caused by the high frequency noise, and the driver feels the rough sound quality, efforts to reduce them with proper NVH measures are indispensable.

Experimental Study of Compressor Surge for 250-hp Class Vehicular Turbocharger (250마력 급 차량용 터보차저 서지현상에 대한 실험적 연구)

  • Lee, Hyungchang;Han, Jaeyoung;Lee, Myeonghee;Im, Seokyoen;Yu, Sangseok
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.1
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    • pp.89-95
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    • 2015
  • A surge phenomenon cause noise and pulsations in a turbo compressor, which is an unstable operating regime. Because surge protection ensures a safe compressor operation, it is important to understand the physics of the surge phenomenon. In this study, the surge characteristics of a 250-hp class turbo-compressor were evaluated experimentally. The experimental parameters were the rotational speed, opening angles of the inlet guide vane and exit valve, and inlet pipe diameter and flow rates of the inlet gases. The results showed that the compressor surge was very sensitive to the gas flow rates, exit pressure, rotational speed, and bypass flow rates.

Measurement and Discrimination Method for the Evaluation of Aero-Pulsation Noise Generated by the Turbocharger System (터보차저의 공기맥동음 평가를 위한 측정 및 판별법)

  • Kim, Jae-Heon;Lee, Jong-Kyu
    • The Journal of the Acoustical Society of Korea
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    • v.26 no.7
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    • pp.361-365
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    • 2007
  • Aero-pulsation noise, generally caused by geometric asymmetry of a rotating device, is one of considerable sources of annoyance in passenger cars using the turbocharged diesel engine. Main source of this noise is the compressor wheel in the turbocharger system, and can be reduced by after-treatment devices such as silencers, but which may increase the manufacturing cost. More effective solution is to improve the geometric symmetry over all, or to control the quality of components by sorting out inferior ones. The latter is more simple and reasonable than the former in view of manufacturing. Thus, an appropriate discrimination method should be needed to evaluate aero-pulsation noise level at the production line. In this paper, we introduce the accurate method which can measure the noise level of aero-pulsation and also present its evaluation criteria. Besides verifying the reliability of a measurement system - a rig test system-, we analyze the correlation between the results from rig tests and those from vehicle tests. The gage R&R method is carried out to check the repeatability of measurements over 25 samples. From the result, we propose the standard specification which can discriminate inferior products from superior ones on the basis of aero-pulsation noise level.

Simulation-based Optimum Allocation of a Resonator for Reducing the Blow Noise of a Turbocharger in a Diesel Engine (디젤 엔진에서의 터보 차저 Blow 소음 저감 위한 시뮬레이션 기반 공명기 위치 최적화)

  • Kang, Yong-Hun;Choi, Dong-Hoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.2
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    • pp.129-134
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    • 2010
  • A diesel engine is equipped with a turbocharger for providing more power at a low engine speed region by supplying charge air to combustion chambers. The turbocharger makes it possible to satisfy stringent emission regulations and customers' demand of enjoying the fun to drive by increasing engine performance. However, the turbocharger has the disadvantage of making BPF(Blade Passing Frequency), hissing, surge, whistle, and blow noises. Among them, reducing the blow noise, a narrow-band noise(a general range : 1800~2000Hz), is possible by using a resonator that controls the narrow frequency band governing the resonance in the intake system. In this study, the optimum location of the resonator is found by employing Boost as a CAE(Computer Aided Engineering) tool and is confirmed by experiments of an engine dynamo test and a real vehicle test.

Identification of Linear and Nonlinear Dynamic Stability Characteristics of a Medium-size High-speed Turbocharger Rotor Supported by 3-lobe Bearings (3-로브 베어링으로 지지된 중형 고속 터보차저 로터의 선형 및 비선형 동적 안정성 특성 규명)

  • Lee, An-Sung;Kim, Byung-Ok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.6
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    • pp.562-569
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    • 2011
  • In this study linear and nonlinear dynamic stability characteristics of a medium-size high-speed turbocharger, whose rotor is supported by two 3-lobe journal bearings, are analyzed to evaluate and identify the effects of its bearing design variables. The rotor has the rated speed of 40,500 rpm and maximum continuous speed of 45,000 rpm. At first, utilizing the linear stability analysis method, bearing designs of yielding stable or unstable LogDecs as small as possible are searched by manipulating with machined bearing clearances and preloads. As next, utilizing the nonlinear analysis method, limit cycles of the rotor responses at the rated and maximum continuous speeds are simulated to check their acceptances. Results have shown that for the turbocharger rotor-bearing system considered, the 3-lobe journal bearing design with a smaller machined clearance and a larger preload are preferred for the stable rotor responses. More importantly, since there exists a good correlation between the linear and nonlinear stability analysis results, it is concluded that firstly the linear stability analysis method may be applied to screen quickly the ranges of bearing designs for stable or least unstable solutions and then, lastly the nonlinear stability analysis method may be deployed to check an absolute motion stability in terms of the limit cycle.

A study about reducing Turbocharger Pulsation of 3 cylinder engine (3 기통 엔진의 터보 차저 맥동 저감에 대한 연구)

  • Seo, Kwanghyun;Cho, Sungyong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.667-669
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    • 2014
  • Development of 3 cylinder turbo charger engine is increasing due to engine down-sizing, cost reduction and emission regulations. However, 3 cylinder engine makes higher Exhaust manifold gas pressure(P3) pulsation than 4 cylinder engine and it generate boosting air with high pulsation. The mechanical waste-gate turbocharger just controlled by the boosting air has higher movement because of this high pulsation boosting air. This causes high vibrations to wasted gate and accelerate wear of the linkage system. So we need to understand out of the exhaust gas pressure pulsation changed by turbocharger compressor pressure(P2) Pulsation. In this study, we discuss how to prevent to abnormal movement of the turbo actuator by stabilized P2 Pulsation.

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